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pythonvariablesnumpy
Rafat
Rafat

Reputation: 137

How to make file name a variable using np.savetxt in python?

Is it possible to make the output filename a variable using np.savetxt? I have multiple input file from where I will read and perform some calculations and output the results in a file. Right now I am changing the file name each time for different output, But is there a way to do it automatically? The code I used is as below:

np.savetxt('ES-0.dat', np.c_[strain_percent, es_avg, es_std])

I would like to change the file name to ES-25.dat, ES 50.dat, ES-75.dat ....etc. This is also dependent upon the input file which I read like this:

flistC11 = glob.glob('ES-0')

Is there also a way to automatically change the input file to ES-25, ES-50, ES-75....etc?

I tried using loops but both the input and output has to be inside ' ' which does not allow me to make it a variable. Any idea how can I solve this problem? My work will be much easier then.

Added information after Saullo Castro's answer:

The file that I'm reading (ES*) consists two simple columns like this:

200 7.94
200 6.55
200 6.01
200 7.64
200 6.33
200 7.96
200 7.92

The whole script is as below:

import numpy as np
import glob
import sys


flistC11 = glob.glob('ES-s*')


#%strain

fdata4 = []
for fname in flistC11:
  load = np.loadtxt(fname)
fdata4.append(load[:,0]) #change to 0=strain or 1=%ES

fdata_arry4=np.array(fdata4)

print fdata_arry4

strain=np.mean(fdata_arry4[0,:])
strain_percent = strain/10

print strain_percent

#ES

fdata5 = []
for fname in flistC11:
  load = np.loadtxt(fname)
fdata5.append(load[:,1]) #change to 0=strain or 1=%ES

fdata_arry5=np.array(fdata5)

print fdata_arry5

es_avg=np.mean(fdata_arry5[0,:])
es_std=np.std(fdata_arry5[0,:])


print es_avg
print es_std

np.savetxt('{0}.dat'.format(fname), np.c_[strain_percent,es_avg,es_std])

Upvotes: 1

Views: 2278

Answers (2)

Saullo G. P. Castro
Saullo G. P. Castro

Reputation: 58915

You can do something like:

flistC11 = glob.glob('ES*')
for fname in flistC11:
    # ...something...
    np.savetxt('{0}.dat'.format(fname), np.c_[strain_percent, es_avg, es_std])

note that using ES* will tell glob() to return the names of all files beggining with ES.

EDIT: Based on your comments it seems you actually want something like this:

import glob

import numpy as np

flistC11 = glob.glob('ES-s*')
for fname in flistC11:
    strains, stresses = np.loadtxt(fname, unpack=True)
    strain = np.mean(strains)
    strain_percent = strain/10
    print fname, strain_percent
    es_avg = np.mean(stresses)
    es_std = np.std(stresses)
    print fname, es_avg, es_std
    np.savetxt('{0}.dat'.format(fname), np.c_[strain_percent, es_avg, es_std])

Upvotes: 1

hpaulj
hpaulj

Reputation: 231385

It's not entirely clear where your error is (where is line 15?), but lets assume it is in the load. You have

fdata4 = []
for fname in flistC11:
  load = np.loadtxt(fname)
fdata4.append(load[:,0]) #change to 0=strain or 1=%ES

I'd suggest changing this to:

fdata4 = []
for fname in flistC11:
  print fname  # check that the names make sense
  load = np.loadtxt(fname)
  print load.shape  # check that the shape is as expected
  # maybe print more of 'load' here
  # I assume you want to collect 'load' from all files, not just the last
  fdata4.append(load[:,0]) #change to 0=strain or 1=%ES
print fdata4

In an Ipython shell, I had no problem producing:

In [90]: flistC11=['ES0','ES1','ES2']
In [91]: for fname in flistC11:
    np.savetxt('{}.dat'.format(fname), np.arange(10))
   ....:     
In [92]: glob.glob('ES*')
Out[92]: ['ES2.dat', 'ES0.dat', 'ES1.dat']

Upvotes: 1

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